Six crew members of a freighter are missing after the ship sank following a collision in the Singapore Strait, the Maritime and Port Authority of Singapore (MPA) said.

The freighter, which was bearing the Antigua and Barbuda flag, collided with a Cayman Islands-registered chemical tanker on Wednesday night (Dec 16), the MPA said in a statement issued past midnight on Thursday.

Six out of 12 members of the freighter’s crew were rescued and taken to the Singapore General Hospital, and search and rescue operations are ongoing for the missing six.

There was no Singaporean crew member on either vessel.

The incident occurred at 8.14pm in Indonesian waters, 11km north-west of Batam island. The freighter, named “Thorco Cloud”, was carrying 560 metric tonnes of bunker fuel. The chemical tanker, named “Stolt Commitment”, sustained minor damage and is in stable condition, said the MPA.

The MPA deployed two patrol craft for search and rescue operations, while the Singapore Civil Defence Force deployed two vessels. Singapore’s Police Coast Guard deployed five boats, which rescued five of the crew members. A sixth was rescued by the chemical tanker.

Indonesian authorities were alerted to the incident by the MPA and have also commenced search and rescue operations. MPA said it is assisting the Indonesian authorities to survey and mark the sunken freighter to ensure navigational safety.

MPA has also issued navigational broadcasts to vessels in the vicinity to keep clear of the area and to report any sightings of the missing crew members.​There is no disruption to shipping traffic or reports of any oil spills in the Singapore Strait currently, the MPA said, adding that it has anti-pollution craft on standby.